Offshore activity is performed on a massive scale in the quest for petroleum and the production of petroleum from discovered pools. It is a common occurrence that structures built in the past to find or develop petroleum are no longer to be used, either because the petroleum pool has become depleted, or was found not to be economically feasible. These structures, such as offshore platforms, drilling rigs, conductors or the like, can become a navigational hazard and must be removed. Also sunken ships, boats, pipelines and other metal objects that have been part of the offshore activity or related or even unrelated activities may become lodged on the ocean bottom and are sought to be removed for a variety of reasons.
In particular, offshore platforms and drilling rigs that have been constructed and then abandoned must be removed to avoid the navigational hazard that would be obvious. Such removal has typically been not too complex because, in one method, it simply involved the use of explosives that may be positioned around the support piling embedded perhaps hundreds of feet into the ocean floor. In some instances, the explosives are lowered within the cylindrical pile and exploded at a level below the mudline so that no remaining portion of the pile is permitted to protrude from the mudline. In such instance, however, the explosion distorts the pile to such an extent that it is not possible to lift the pile out from within its surrounding jacket that extends from the platform down to but not below the mudline. Even with such a disadvantage, explosive devices have continued to be utilized in the past and have admittedly been successful in the total removal of the piling down to at least the required 15 feet below the mudline. This method, even though in widespread use, is now no longer permitted by the United States Government due to the environmental impact caused by the explosion.
It has been found that explosive devices detonated no matter how far below sea level cause great damage to the marine life, not only due to the explosive force which has the effect of sending shock waves for many miles, but also due to the chemical remnants of the explosive that remain in the sea to create havoc with the marine life. Additionally, the noise emanating from the blast produces sound waves that are harmful to the living creatures of the sea.
Thus, though it is still essential that these structures be removed, the use of explosives is illegal and no longer available in U.S. territorial waters. It is anticipated that other governments will appreciate the significant hazard posed by explosives to marine life and require the removal of such undersea structures in areas within their own territorial waters to be limited to non-explosive techniques and the present invention in particular.